>>HN39 has done an energy matching simulation (segment by segment) combined with aerodynamic assumptions. (Believe it was in the prior Tech thread.) His conclusion was that the final climb from FL375 to FL 380 was ballistic, i.e. the aircraft started upward on the last dregs of its lift and decelerated below actual level flight stall speed in the climb. This would allow the aircraft to fly below actual level flight stall speed and continue trimming nose up because the AOA had not yet become high enough to shut down the automatic pitch trimming. When gravity caught up with the aircraft and it began to fall, it then went rapidly well past the stall AOA and shut down the automatic pitch trim at 13 degrees ANU.
>>HN39 is very good with this type of thing, and we Physics duffers should respect his knowledge.
>>HN39, if I have gilded the Lilly too badly please correct me.
Yes, I've read that and as explained, those calculations is missing something. As such I started my article. Only for vertical movements, the trade-off in energy can be applied without further side conditions. When changing a horizontal speed into height, other aspects start to act up. If you want more explanation, let me know. I'm aware it's written down pretty condensed.
Maybe I should have mentioned before: I'm not a pilot, though do have a degree in Applied Physics (which includes Control systems behavior at the University I went - some years ago- ).
And: My description also suggests why there are around 10 reported similar upsets. Unexplained upsets without any plausible technical cause. And no, no conspiracies .....